Abstract:
This study aimed to understand the origin and dynamics of pedogenic carbonate in Antarctic soils, with a long-term view to understanding the formation of carbonate and the storage and turnover of inorganic carbon in desert soils. Soil pits were dug on surfaces of varying age in eastern Taylor Valley and around Lake Wellman. Each pit was described and volumetrically sampled to enable laboratory ... determination of total carbonate percentage. Matrix samples were taken and analysed to determine carbonate isotopic composition and soil chemistry (pH, electrical conductivity, soil solution composition and percent carbonate). Selected carbonate samples were submitted for radiocarbon dating. Carbonate coatings on rocks were also sampled for isotopic analyses and dating. The abundance and morphology of carbonate coatings on surface clasts were recorded along transects on surfaces of different age. Gas chambers and gas sampling tubes were also installed at each site. Soil gas samples were taken from tubes within soil profiles for analysis of CO2 concentration and isotopic composition. Gas samples from surface chambers were taken to calculate soil respiration rate. Campbell Scientific dataloggers were used for recording data from soil moisture and temperature probes (Stevens Vitel Hydraprobes), as well as from a temporary met station logging above ground temperature and relative humidity, wind speed and direction, and solar radiation at twenty minute intervals at each of the gas sampling sites, over periods ranging from 7 to 14 days. Soil moisture sensors beneath surface clasts provided data on the duration of liquid moisture beneath rocks.